Good day to you, Radicons,
I'm not what you call an expert on kitbashing, but I did a little mod to my Salvage toy I thought I could share. I apologize, because I did not take pictures due to low quality camera, so I'll try using Flash-drawn images for reference. I kept it simple just to get the point across. I'm sure if you have the toy, you'll be able to follow this tutorial.

This is how far the gun usually goes. Sure, it's okay, but it feels like it's in the way. And if you're the kind of person who puts weapons on characters' hands, this guy might not be able to hold certain ones due to the gun being in the way. I'm going to teach you how to fold it down.

First, flip the gun up like it is in the alt. mode.

Notice the way the hinge. The top part is rounded so you can move the gun up, but the bottom part is blocky to keep you from folding it down.

Basically, what you want to do is shave the plastic off of the edge of the square part, until it's rounded like the upper part as shown. I used scissors, but please use whatever safe tool you have for plastic shaving.

And this is the end result! It would be even nicer if you could fold it all the way under the forearm, but this will have to do.

I hope this little mod is helpful. Again, I apologize for the lack of actual photos, but I think this should be a good enough guide.